1. Field of the Invention
The present invention relates to a presentation support system which can facilitate formation of materials for presentation, thereby effectively supporting the presentation.
2. Description of the Related Art
In order to form materials for presentation, it is necessary to collect data associated with the contents of presentation and to consider a method of presenting (representing) the collected data in accordance with the contents of data. Therefore, it generally takes a very long time to form materials. However, it is generally very difficult to collect a satisfactory amount of data required to form presentation materials. In addition, it is in many cases hard to determine a method of effectively presenting the collected data. For these reasons, formation of presentation materials which can satisfactory attract attention of audience is not easy, and formed presentation materials are often interpreted in a manner which is different from the intention of presentation.
"Lotus 1-2-3" available from Lotus Development Corporation, for example, is known as a means for forming presentation materials. This apparatus (system) converts, e.g., item names, attribute values for the respective items, and titles, which are input in the form of a table by a user as shown in FIG. 1, into the form of a graph designated by the user, as shown in FIG. 2, and outputs this graph. That is, the system represents collected (user-input) numeric data in a user-designated representation form, such as a bar chart or a line graph, and uses this as a picture for presentation materials. The use of such a means makes it possible to relatively easily form neat graphs to be used as presentation materials.
It is hard to say, however, that data thus graphically illustrated satisfactorily represents the contents of data to be interpreted or its background data. In addition, the level of requirements of users has been increased recently as these graphic techniques have been developed. That is, a demand has increasingly arisen for a system which can not only perform transmission of superficial data but also visualize contents to be represented using formed graphs more clearly.
Conventionally, as described above, it is generally difficult to easily form presentation materials. For example, in order to represent the contents of data in the form of a graph using a photograph or the like, which is used to communicate the intention of presentation, for a background, a presenter must perform a work of cutting and pasting the graph, which is formed on the basis of the collected data, on the photograph or the like. In addition, it is very difficult to obtain presentation data such as images or sounds adapted to the intention of presentation, and this further increases a work-load.
Conventionally, in generating desired object data by means of such computer graphics, a graphics designer designs individual data by using modeling software or the like.
When, however, it is required to make a change in object data once completed in this manner, the entire object data must be generated again from the beginning because existing modeling software does not have control points enough to meet the modification in object data.
For this reason, modeling software capable of simplifying generation and modification of object data has been developed. This software constitutes object data using a plurality of components and selectively combines necessary components from various prepared components, thereby generating desired object data. When object data need be changed, the software replaces a component to be changed with another to modify the object data.
This modeling software, however, has a problem that when formed components are to be combined, the sizes of the components or the link relationships between the components must be reset, and this results in a cumbersome operation.
As a method of creating a moving object, a method of integrally defining an entire object (like a meta ball) and a method of linking primitives are available. The latter method can be handled more easily than the former in defining a complicated object in motion. As described in "Formation of Animation by Interactive Script Method" (Data Processing Society of Japan CG & CAD, February 1989), there is a method of describing primitive link data using an exclusive modeling language.
Conventionally, creation of this linked body has been attempted by simultaneously linking primitives in parallel, and the link data has been described exclusively for each of moving objects as position data which is derived from the shape of a primitive figure to be linked and is used to link the primitives. For this reason, when moving objects to be represented are increased in number, the amount of data is also increased. In addition, when, for example, an upper arm of a human being, which is represented by a cube, is to be represented by a rectangular parallelepiped, data of the entire human being is newly required. This makes it difficult to perform local deletion and re-creation.
Conventional animation generation methods, for example, a method disclosed in Published Unexamined Japanese Patent Application No. 1-193974 gives movement to an object using a new function and parameters in an environment having an influence and does not relate to a method of creating an object. Therefore, in representing the movement of an object itself, not only a complicated function is required, but also the processing amount and the data quantity are doubled in order to perform both creation of the object and representation of the movement. In addition, when an object is created by a linked body as described above, in order to move a limb constituted by an arm and a hand, for example, the movement of the hand must be described in consideration of the movement of the arm so that the arm and the hand are not separated from each other. That is, since the movements of all of linked primitives are related to each other, description of data for giving the movements is complicated.
In an image generated by calculations performed by a computer, the presence of shadows makes a large contribution for human beings to recognize the state of a three-dimensional space represented by the image. For this reason, various methods of calculating shadows also have been studied in the field of computer graphics.
In the field of such computer graphics, a demand has arisen for an application of simulating an indoor space realistically and interactively as the range of applications of this field has been widened. The characteristic feature of the indoor space is that a plurality of light sources, such as spotlights, each of which has illumination characteristics such as a brightness, a color, and a manner of spread of light are present, and these light sources give brightness to objects and produce shadows. Since real light sources have their "sizes", "soft shadows" with indefinite shadow boundaries are produced. Therefore, the field of computer graphics also requires a technique capable of calculating soft shadows obtained by light sources having illumination characteristics.
As representative examples of such a technique, the following various methods have been conventionally proposed.
(a) A method of performing simple mapping by using a single light source. According to this method, it is possible to perform processing with a low calculation cost and to produce a pseudo shadow at a high speed. In addition, since a shadow is projected only on a flat plane, a shadow with a sharp boundary can be obtained.
(b) A method of correctly calculating the boundary of a shadow by using perfect parallel light or a point source with no size as a model. This method provides a shadow having a sharp boundary. However, an arithmetic operation cost is significantly increased as light sources are increased in number.
(c) A method of calculating a distance that light travels from a light source by using a Z buffer method and determining upon application of the Z buffer method from a view point whether a point of each depth is a shadow. This method can produce soft shadows with its high representation power. However, the method requires a high calculation cost and a large memory.
(d) A method of calculating an equilibrium state of exchange of optical energy between objects by using a perfect diffusion light source as a model assuming that objects other than the light source absorb or radiate light. In this method, although a shadow having a soft boundary can be produced, the calculation cost is very high. For this reason, a method of gradually calculating the exchange of optical energy to update an image to one having a higher quality stepwise is also available. However, the calculation cost of this method is still high.
Thus, of these conventional methods as described above, those which can provide a high-speed display with a low cost can produce only a shadow with a sharp boundary. On the other hand, those which can produce a soft shadow require a high calculation cost and therefore cannot be used in an interactive system.